On the one hand, if you're in a hurry and only need a basic one-page site, the best thing to do is to do it yourself. On the other hand, if you need your website up and running quickly and you need a lot of features, you should probably pay someone. Having more time basically gives you two things. You can choose to take some courses and learn the skills you need to create your own WordPress site, but a lot of people simply pay a developer to create their website for them.
To make sure you're paying the right person for your web design project, you need to understand the difference. The time you spend designing, creating, and implementing could end up costing you more in lost business revenue than what you pay to an outside contractor. So, back to the original question, do you really need to pay someone to create your website? As you can see now, the answer depends on your specific business situation.